1. Field
Apparatuses and methods consistent with exemplary embodiments relate to processing an image and, more particularly, to image processing that can effectively display an image by using an optimized dynamic range compression (DRC) technique.
2. Description of the Related Art
The DRC technique is used for increasing brightness of a portion of an image that is not clearly seen in a dark region and a bright region of the image by compressing a dynamic range that indicates a brightness ratio between a brightest region and a darkest region in the image. Generally, in order to increase brightness of an image, a tone-mapping function is used on an entire image. However, contrast is reduced and information is damaged on a specific region of the image.
It is known that a retinex algorithm using the DRC technique, which is designed based on a retinex theory, exhibits a high performance in increasing brightness of an image. The retinex algorithm is a method of synthesizing an image by reducing an effect of illuminance, increasing reflectance of an input image after estimating illuminance of the input image by using a Gaussian filter and obtaining a reflectance image that includes a feature of an object by removing the illuminance of the input image. However, in order to estimate illuminance, a sufficiently large Gaussian filter is needed, and a halo artifact occurs on a portion of an image which has large brightness differences.